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2.
Cancer Chemother Pharmacol ; 92(6): 455-464, 2023 12.
Article in English | MEDLINE | ID: mdl-37505272

ABSTRACT

The first-in-patient (FIP) starting dose for oncology agents should be reasonably safe and provide potential therapeutic benefit to the patient. For late-stage oncology patients, this dose is often based on the ICH S9 guidance, which was developed primarily based on experience with cytotoxic chemotherapeutic agents using the rodent STD10 or non-rodent HNSTD and an appropriate safety factor. With the increase in molecularly targeted chemotherapeutics, it is prudent to re-evaluate how the FIP dose is derived to ensure that the appropriate balance between risk and therapeutic benefit to the patient is achieved. Blinded data on 92 small molecule oncology compounds from 12 pharmaceutical companies who are members of the IQ DruSafe consortium were gathered to investigate if a NOAEL-based starting dose without a safety factor would have been tolerated in the FIP trial and if so, estimating how many dose escalation cohorts could have been reduced. Our analysis suggests that the NOAEL-based alternative starting dose would have been tolerated in most cases evaluated, with an anticipated mean reduction of 2.3 cohorts. Of the 12 cases where the alternative approach resulted in a starting dose that would have exceeded the MTD/RP2D, none of the nonclinical toxicities in these cases were considered irreversible and would be monitorable in all but one instance. Most non-tolerated cases were within two-threefold of the MTD/RP2D, with the clinical AEs considered manageable and mitigated by dose de-escalation. No one method of FIP dose calculation will likely be appropriate for all oncology small molecules and starting dose selection should be performed using a case-by-case approach. However, the NOAEL-based method that does not utilize a safety factor should be considered when appropriate to minimize the number of patients exposed to sub-therapeutic doses of an investigational oncology agent and accelerating development to RP2D.


Subject(s)
Antineoplastic Agents , Neoplasms , Humans , No-Observed-Adverse-Effect Level , Antineoplastic Agents/adverse effects , Maximum Tolerated Dose , Neoplasms/drug therapy , Medical Oncology , Dose-Response Relationship, Drug
3.
J Crim Justice ; 86: 102050, 2023.
Article in English | MEDLINE | ID: mdl-36911596

ABSTRACT

On March 10, 2020, the Governor of the State of Michigan, USA, declared a state of emergency in response to COVID-19. Within days, schools were closed; in-person dining was restricted; and lockdowns and precautionary stay-at-home orders were issued. These restrictions dramatically impacted the mobility of offenders and victims through space and time. As routine activities were forced to change and crime generators were closed, did hot spots and risky locations for victimization change as well? The purpose of this research is to analyze potential shifts in high-risk areas for sexual assaults before, during, and after COVID-19 restrictions. Using data from the City of Detroit, Michigan, USA, optimized hot spot analysis and Risk Terrain Modeling (RTM) were used to identify critical spatial factors for the occurrence of sexual assaults before, during, and after COVID-19 restrictions. The results suggested that hot spot areas for sexual assaults were more concentrated during the COVID timeframe, compared to the Pre-COVID timeframe. While blight complaints, public transit stops, points of sale for liquor, and the locations of drug arrests were consistent risk factors for sexual assaults before and after COVID restrictions, other factors, such as casinos and demolitions, were only influential in the COVID period.

4.
Regul Toxicol Pharmacol ; 117: 104746, 2020 Nov.
Article in English | MEDLINE | ID: mdl-32911461

ABSTRACT

Pharmaceutic products designed to perturb the function of epigenetic modulators have been approved by regulatory authorities for treatment of advanced cancer. While the predominant effort in epigenetic drug development continues to be in oncology, non-oncology indications are also garnering interest. A survey of pharmaceutical companies was conducted to assess the interest and concerns for developing small molecule direct epigenetic effectors (EEs) as medicines. Survey themes addressed (1) general levels of interest and activity with EEs as therapeutic agents, (2) potential safety concerns, and (3) possible future efforts to develop targeted strategies for nonclinical safety assessment of EEs. Thirteen companies contributed data to the survey. Overall, the survey data indicate the consensus opinion that existing ICH guidelines are effective and appropriate for nonclinical safety assessment activities with EEs. Attention in the framework of study design should, on a case by case basis, be considered for delayed or latent toxicities, carcinogenicity, reproductive toxicity, and the theoretical potential for transgenerational effects. While current guidelines have been appropriate for the nonclinical safety assessments of epigenetic targets, broader experience with a wide range of epigenetic targets will provide information to assess the potential need for new or revised risk assessment strategies for EE drugs.


Subject(s)
Drug Industry/standards , Drug and Narcotic Control , Epigenesis, Genetic/drug effects , Pharmaceutical Preparations/standards , Surveys and Questionnaires , Animals , Drug Evaluation, Preclinical/standards , Drug Evaluation, Preclinical/trends , Drug Industry/trends , Drug and Narcotic Control/trends , Drug-Related Side Effects and Adverse Reactions/epidemiology , Drug-Related Side Effects and Adverse Reactions/prevention & control , Epigenesis, Genetic/genetics , Humans , Pharmaceutical Preparations/administration & dosage , Risk Assessment/standards , Risk Assessment/trends
5.
Cancer Cell ; 36(2): 194-209.e9, 2019 08 12.
Article in English | MEDLINE | ID: mdl-31408619

ABSTRACT

Cancer-associated mutations in genes encoding RNA splicing factors (SFs) commonly occur in leukemias, as well as in a variety of solid tumors, and confer dependence on wild-type splicing. These observations have led to clinical efforts to directly inhibit the spliceosome in patients with refractory leukemias. Here, we identify that inhibiting symmetric or asymmetric dimethylation of arginine, mediated by PRMT5 and type I protein arginine methyltransferases (PRMTs), respectively, reduces splicing fidelity and results in preferential killing of SF-mutant leukemias over wild-type counterparts. These data identify genetic subsets of cancer most likely to respond to PRMT inhibition, synergistic effects of combined PRMT5 and type I PRMT inhibition, and a mechanistic basis for the therapeutic efficacy of PRMT inhibition in cancer.


Subject(s)
Antineoplastic Agents/pharmacology , Enzyme Inhibitors/pharmacology , Ethylenediamines/pharmacology , Leukemia, Myeloid, Acute/drug therapy , Protein-Arginine N-Methyltransferases/antagonists & inhibitors , Pyrroles/pharmacology , RNA Splicing/drug effects , RNA, Neoplasm/metabolism , Animals , Antineoplastic Agents/pharmacokinetics , Catalysis , Enzyme Inhibitors/pharmacokinetics , Ethylenediamines/pharmacokinetics , Gene Expression Regulation, Neoplastic , Gene Regulatory Networks , Humans , K562 Cells , Leukemia, Myeloid, Acute/genetics , Leukemia, Myeloid, Acute/metabolism , Mice, Inbred C57BL , Mice, Transgenic , Protein-Arginine N-Methyltransferases/genetics , Protein-Arginine N-Methyltransferases/metabolism , Pyrroles/pharmacokinetics , RNA, Neoplasm/genetics , Repressor Proteins/antagonists & inhibitors , Repressor Proteins/metabolism , THP-1 Cells , Tumor Cells, Cultured , U937 Cells , Xenograft Model Antitumor Assays
6.
Cancer Cell ; 36(1): 100-114.e25, 2019 07 08.
Article in English | MEDLINE | ID: mdl-31257072

ABSTRACT

Type I protein arginine methyltransferases (PRMTs) catalyze asymmetric dimethylation of arginines on proteins. Type I PRMTs and their substrates have been implicated in human cancers, suggesting inhibition of type I PRMTs may offer a therapeutic approach for oncology. The current report describes GSK3368715 (EPZ019997), a potent, reversible type I PRMT inhibitor with anti-tumor effects in human cancer models. Inhibition of PRMT5, the predominant type II PRMT, produces synergistic cancer cell growth inhibition when combined with GSK3368715. Interestingly, deletion of the methylthioadenosine phosphorylase gene (MTAP) results in accumulation of the metabolite 2-methylthioadenosine, an endogenous inhibitor of PRMT5, and correlates with sensitivity to GSK3368715 in cell lines. These data provide rationale to explore MTAP status as a biomarker strategy for patient selection.


Subject(s)
Antineoplastic Agents/pharmacology , Enzyme Inhibitors/pharmacology , Protein-Arginine N-Methyltransferases/antagonists & inhibitors , Purine-Nucleoside Phosphorylase/deficiency , Alternative Splicing , Antineoplastic Agents/chemistry , Biomarkers , Cell Line, Tumor , Drug Synergism , Enzyme Inhibitors/chemistry , Humans , Methylation , Models, Molecular , Molecular Conformation , Molecular Structure , Protein Binding , Protein-Arginine N-Methyltransferases/chemistry , Substrate Specificity
7.
Toxicol Appl Pharmacol ; 334: 100-109, 2017 11 01.
Article in English | MEDLINE | ID: mdl-28893587

ABSTRACT

The contribution of animal testing in drug development has been widely debated and challenged. An industry-wide nonclinical to clinical translational database was created to determine how safety assessments in animal models translate to First-In-Human clinical risk. The blinded database was composed of 182 molecules and contained animal toxicology data coupled with clinical observations from phase I human studies. Animal and clinical data were categorized by organ system and correlations determined. The 2×2 contingency table (true positive, false positive, true negative, false negative) was used for statistical analysis. Sensitivity was 48% with a 43% positive predictive value (PPV). The nonhuman primate had the strongest performance in predicting adverse effects, especially for gastrointestinal and nervous system categories. When the same target organ was identified in both the rodent and nonrodent, the PPV increased. Specificity was 84% with an 86% negative predictive value (NPV). The beagle dog had the strongest performance in predicting an absence of clinical adverse effects. If no target organ toxicity was observed in either test species, the NPV increased. While nonclinical studies can demonstrate great value in the PPV for certain species and organ categories, the NPV was the stronger predictive performance measure across test species and target organs indicating that an absence of toxicity in animal studies strongly predicts a similar outcome in the clinic. These results support the current regulatory paradigm of animal testing in supporting safe entry to clinical trials and provide context for emerging alternate models.


Subject(s)
Databases, Factual , Translational Research, Biomedical , Animals , Drug Evaluation, Preclinical , Drug Industry , Drug-Related Side Effects and Adverse Reactions , Humans , Models, Animal , Risk Assessment
8.
Birth Defects Res B Dev Reprod Toxicol ; 104(6): 244-52, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26626128

ABSTRACT

Dabrafenib (DAB), an inhibitor of BRAF kinase activity, is approved for metastatic melanoma with a BRAF V600E mutation. In support of pediatric cancer development, a nonclinical juvenile rat toxicity study was conducted in which females had early vaginal opening (VO). It was hypothesized that the early VO was not indicative of sexual maturation, but a result of a local effect on the vagina. An investigative study was conducted that mimicked the definitive study design, with rats given DAB or vehicle orally from Postnatal Day (PND) 7 to 35 and with necropsy subsets just before VO, at the first and second estrus, along with age-matched controls. Histopathology was performed on reproductive tissues, including immunohistochemistry for BRAF expression. VO occurred earlier in DAB females than in controls (PND 27.2 vs. 31.5); however, the timing of the first estrus was unaffected (PND 34.0 vs. 33.0). DAB-treated females evaluated just before VO (PND 22.0) had mostly immature reproductive tracts with no evidence of ovulation, similar to age-matched controls; however, DAB-treated females had keratinized and histologically open vaginas. Also, there was raised skin around the urogenital area, which correlated with hyperplasia/keratosis of the vulvar skin and keratinization of the distal vagina. BRAF expression (evaluated in controls) was localized to these tissues. Thus, early VO in rats given DAB likely represents a local effect accelerating vaginal keratinization to become open and not accelerated sexual maturation.


Subject(s)
Imidazoles/pharmacology , Oximes/pharmacology , Protein Kinase Inhibitors/pharmacology , Proto-Oncogene Proteins B-raf/antagonists & inhibitors , Sexual Maturation/drug effects , Vagina/physiology , Animals , Estrus/drug effects , Female , Immunohistochemistry , Proto-Oncogene Proteins B-raf/metabolism , Rats, Sprague-Dawley , Vagina/cytology , Vagina/drug effects
9.
Cancer Cell ; 28(1): 57-69, 2015 Jul 13.
Article in English | MEDLINE | ID: mdl-26175415

ABSTRACT

Epigenetic dysregulation has emerged as an important mechanism in cancer. Alterations in epigenetic machinery have become a major focus for targeted therapies. The current report describes the discovery and biological activity of a cyclopropylamine containing inhibitor of Lysine Demethylase 1 (LSD1), GSK2879552. This small molecule is a potent, selective, orally bioavailable, mechanism-based irreversible inactivator of LSD1. A proliferation screen of cell lines representing a number of tumor types indicated that small cell lung carcinoma (SCLC) is sensitive to LSD1 inhibition. The subset of SCLC lines and primary samples that undergo growth inhibition in response to GSK2879552 exhibit DNA hypomethylation of a signature set of probes, suggesting this may be used as a predictive biomarker of activity.


Subject(s)
Antineoplastic Agents/administration & dosage , Benzoates/administration & dosage , Cyclopropanes/administration & dosage , DNA Methylation/drug effects , Enzyme Inhibitors/administration & dosage , Histone Demethylases/antagonists & inhibitors , Lung Neoplasms/drug therapy , Small Cell Lung Carcinoma/drug therapy , Administration, Oral , Animals , Antineoplastic Agents/pharmacology , Benzoates/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Cyclopropanes/pharmacology , Enzyme Inhibitors/pharmacology , Epigenesis, Genetic/drug effects , Gene Expression Regulation, Neoplastic/drug effects , Histone Demethylases/genetics , Humans , Lung Neoplasms/genetics , Lung Neoplasms/pathology , Mice , Molecular Sequence Data , Small Cell Lung Carcinoma/genetics , Small Cell Lung Carcinoma/pathology , Xenograft Model Antitumor Assays
10.
J Med Chem ; 52(5): 1408-15, 2009 Mar 12.
Article in English | MEDLINE | ID: mdl-19222165

ABSTRACT

N-tert-Butyl isoquine (4) (GSK369796) is a 4-aminoquinoline drug candidate selected and developed as part of a public-private partnership between academics at Liverpool, MMV, and GSK pharmaceuticals. This molecule was rationally designed based on chemical, toxicological, pharmacokinetic, and pharmacodynamic considerations and was selected based on excellent activity against Plasmodium falciparum in vitro and rodent malaria parasites in vivo. The optimized chemistry delivered this novel synthetic quinoline in a two-step procedure from cheap and readily available starting materials. The molecule has a full industry standard preclinical development program allowing first into humans to proceed. Employing chloroquine (1) and amodiaquine (2) as comparator molecules in the preclinical plan, the first preclinical dossier of pharmacokinetic, toxicity, and safety pharmacology has also been established for the 4-aminoquinoline antimalarial class. These studies have revealed preclinical liabilities that have never translated into the human experience. This has resulted in the availability of critical information to other drug development teams interested in developing antimalarials within this class.


Subject(s)
Aminoquinolines/pharmacology , Antimalarials/pharmacology , Benzylamines/pharmacology , Aminoquinolines/chemical synthesis , Aminoquinolines/chemistry , Aminoquinolines/pharmacokinetics , Aminoquinolines/toxicity , Amodiaquine/analogs & derivatives , Animals , Antimalarials/chemical synthesis , Antimalarials/pharmacokinetics , Antimalarials/toxicity , Benzylamines/chemical synthesis , Benzylamines/chemistry , Benzylamines/toxicity , Cytochrome P-450 Enzyme Inhibitors , Dogs , Drug Evaluation, Preclinical , Drug Resistance , Female , Haplorhini , Heme/chemistry , Humans , Malaria/drug therapy , Mice , Models, Molecular , Plasmodium berghei/drug effects , Plasmodium falciparum/drug effects , Plasmodium yoelii , Rats , Structure-Activity Relationship
11.
Violence Vict ; 23(5): 637-51, 2008.
Article in English | MEDLINE | ID: mdl-18958990

ABSTRACT

The current research explores two important issues related to the study of bystander intervention during nonfatal violent victimization. First, using data from the National Crime Victimization Survey (NCVS), conjunctive analysis of case configurations is conducted to identify the most dominant situational contexts in which a bystander is present during violent crime. Second, the prevalence of responses in which a bystander helps or hurts during these events is determined. Results and the analytical approach used in this investigation are discussed in terms of their implications for future research on the normative and deviant reactions to crime by third parties and its victims.


Subject(s)
Crime Victims/statistics & numerical data , First Aid/statistics & numerical data , Helping Behavior , Social Perception , Violence/statistics & numerical data , Aggression , Female , Humans , Interpersonal Relations , Male , Prevalence , Social Environment , United States/epidemiology
12.
J Virol ; 80(19): 9667-75, 2006 Oct.
Article in English | MEDLINE | ID: mdl-16973571

ABSTRACT

The NSs protein of Bunyamwera virus (Bunyaviridae) is an antiapoptotic interferon antagonist involved in silencing host protein expression by interfering with mRNA synthesis. Here, we show that the ability to inhibit both host transcription and the interferon response is linked to interaction of NSs with the MED8 component of Mediator, a protein complex necessary for mRNA production. The interacting domain on NSs was mapped to the C-terminal region, which contains amino acids conserved among orthobunyavirus NSs proteins. A recombinant virus in which the interacting domain in NSs was deleted had strongly reduced ability to inhibit host protein expression and was unable to inhibit the interferon response. This study provides further information on the mechanisms by which bunyavirus nonstructural proteins are involved in pathogenesis.


Subject(s)
Interferons/antagonists & inhibitors , Orthobunyavirus/metabolism , Transcription Factors/metabolism , Viral Proteins/metabolism , Amino Acid Sequence , Animals , Base Sequence , Cell Line , Cricetinae , DNA-Directed RNA Polymerases/metabolism , Humans , Immunity, Innate/immunology , Interferons/genetics , Interferons/immunology , Mediator Complex , Molecular Sequence Data , Orthobunyavirus/chemistry , Orthobunyavirus/genetics , Orthobunyavirus/immunology , Protein Binding , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Transcription Factors/genetics , Two-Hybrid System Techniques , Viral Proteins/chemistry , Viral Proteins/genetics
13.
J Virol ; 79(9): 5326-36, 2005 May.
Article in English | MEDLINE | ID: mdl-15827147

ABSTRACT

Respiratory syncytial virus (RSV) is an important human pathogen that can cause severe and life-threatening respiratory infections in infants, the elderly, and immunocompromised adults. RSV infection of HEp-2 cells induces the activation of RhoA, a small GTPase. We therefore asked whether RhoA signaling is important for RSV replication or syncytium formation. The treatment of HEp-2 cells with Clostridium botulinum C3, an enzyme that ADP-ribosylates and specifically inactivates RhoA, inhibited RSV-induced syncytium formation and cell-to-cell fusion, although similar levels of PFU were released into the medium and viral protein expression levels were equivalent. Treatment with another inhibitor of RhoA signaling, the Rho kinase inhibitor Y-27632, yielded similar results. Scanning electron microscopy of C3-treated infected cells showed reduced numbers of single blunted filaments, in contrast to the large clumps of long filaments in untreated infected cells. These data suggest that RhoA signaling is associated with filamentous virus morphology, cell-to-cell fusion, and syncytium formation but is dispensable for the efficient infection and production of infectious virus in vitro. Next, we developed a semiquantitative method to measure spherical and filamentous virus particles by using sucrose gradient velocity sedimentation. Fluorescence and transmission electron microscopy confirmed the separation of spherical and filamentous forms of infectious virus into two identifiable peaks. The C3 treatment of RSV-infected cells resulted in a shift to relatively more spherical virions than those from untreated cells. These data suggest that viral filamentous protuberances characteristic of RSV infection are associated with RhoA signaling, are important for filamentous virion morphology, and may play a role in initiating cell-to-cell fusion.


Subject(s)
Respiratory Syncytial Viruses/physiology , Signal Transduction , rhoA GTP-Binding Protein/metabolism , ADP Ribose Transferases/pharmacology , Amides/pharmacology , Botulinum Toxins/pharmacology , Cell Line , Giant Cells/ultrastructure , Humans , Pyridines/pharmacology , Respiratory Syncytial Viruses/drug effects , Respiratory Syncytial Viruses/ultrastructure , Virus Replication , rhoA GTP-Binding Protein/antagonists & inhibitors
14.
J Virol ; 78(11): 5679-85, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15140965

ABSTRACT

Artificial minigenomes are powerful tools for studying the replication and transcription of negative-strand RNA viruses. Bunyamwera virus (BUN; genus Orthobunyavirus, family Bunyaviridae) is an arbovirus that shows fundamental biological differences when replicating in mammalian versus mosquito cells. To study BUN RNA synthesis in mosquito cells, we developed a bacteriophage T7 RNA polymerase-based minireplicon system similar to that described previously for mammalian cells. An Aedes albopictus C6/36-derived mosquito cell line stably expressing T7 RNA polymerase was established. Viral proteins and artificial minigenomes (containing Renilla luciferase as a reporter) were transcribed and expressed in these cells from transfected T7 promoter-containing plasmids. Transcription of the minigenome required two viral proteins, the nucleocapsid protein N and the RNA-dependent RNA polymerase L, a situation similar to that in mammalian cells. However, unlike the situation in mammalian cells, the viral polymerase was not inhibited by the viral nonstructural protein NSs. We also report that promoter strength is different for vertebrate versus invertebrate cells. The development of this system opens the way for a detailed comparison of bunyavirus replication in cells of disparate phylogeny.


Subject(s)
Aedes/virology , Bunyamwera virus/physiology , Replicon , Virus Replication , Animals , DNA-Directed RNA Polymerases/metabolism , Promoter Regions, Genetic , Protein Biosynthesis , Transcription, Genetic , Viral Proteins
15.
J Immunol ; 172(8): 5078-85, 2004 Apr 15.
Article in English | MEDLINE | ID: mdl-15067091

ABSTRACT

Lupus-prone New Zealand Black and New Zealand White mice produce high serum levels of the endogenous retroviral envelope protein gp70 and develop an Ab response to this autoantigen as part of their autoimmune disease. Linkage analysis of two crosses involving New Zealand and BALB/c mice mapped these traits to a group of overlapping loci, including a novel locus on proximal chromosome 12. This locus was linked with serum gp70 and the autoimmune response against it. The linkage of serum gp70 levels to a previously described locus on distal chromosome 4 was also confirmed. Sequence analysis of a candidate gene on distal chromosome 4, Fv1, provided support that this gene may be associated with the control of serum gp70 levels in both New Zealand Black and New Zealand White mice. Linkage data and statistical analysis confirmed a close correlation between gp70 Ag and anti-gp70 Ab levels, and together gave support to the concept that a threshold level of gp70 is required for the production of anti-gp70 Abs. Serum levels of anti-gp70 Abs were closely correlated with the presence of renal disease, more so than anti-dsDNA Abs. Understanding the genetic basis of this complex autoantigen-autoantibody system will provide insight into the pathogenesis of lupus in mice, which may have implications for human disease.


Subject(s)
Antibodies, Viral/biosynthesis , Gene Expression Regulation/immunology , Genetic Markers/immunology , Glycoproteins/immunology , Retroviridae/immunology , Viral Envelope Proteins/immunology , Animals , Antibodies, Viral/blood , Chromosome Mapping , Crosses, Genetic , Female , Genetic Linkage , Genetic Predisposition to Disease , Glomerulonephritis/genetics , Glomerulonephritis/immunology , Glycoproteins/blood , Mice , Mice, Congenic , Mice, Inbred BALB C , Mice, Inbred NZB , Proteins/genetics , Species Specificity , Viral Envelope Proteins/blood
16.
Toxicol Pathol ; 31(5): 554-61, 2003.
Article in English | MEDLINE | ID: mdl-14692624

ABSTRACT

Recombinant human interleukin-18 (rHuIL-18) is currently in clinical trials for treatment of cancer. This report presents results of preclinical toxicity studies with rHuIL-18 in cynomolgus monkeys and recombinant murine IL-18 (rMuIL-18) in mice. The rHuIL-18 was administered intravenously in 1 or 2 different 5-day cycles at doses 0.3 to 75 mg/kg/day in monkeys. Decreases in red cell mass, neutrophil, and platelet counts, increases in monocyte and large unstained cell counts, and lymphoid hyperplasia in spleen and lymph nodes were mild, reversible, and likely related to the pharmacologic activity of IL-18. The only toxic effect was protein cast nephropathy, secondary to coprecipitation of administered IL-18 and Tamm-Horsfall protein in the distal nephron, that only occurred at 75 mg/kg/day. Other adverse effects of rHuIL-18 were related to strong immunogenicity in monkeys and were manifest only during a second dosing cycle. The rMuIL-18, at similar dosing levels and cycles in mice, resulted in reduced red cell mass, increased white blood cell counts, spleen and lymph node hyperplasia, and mild, reversible changes in intestine, liver, and lungs. Protein cast nephropathy occurred in mice at doses > or = 30 mg/kg/day. In conclusion, preclinical safety studies showed that rIL-18 was well tolerated at pharmacologically active doses in both monkeys and mice.


Subject(s)
Interleukin-18/toxicity , Animals , Drug Screening Assays, Antitumor , Female , Humans , Hyperplasia , Immunohistochemistry , Injections, Intravenous , Interleukin-18/administration & dosage , Interleukin-18/pharmacokinetics , Kidney/drug effects , Kidney/pathology , Kidney/ultrastructure , Lymph Nodes/drug effects , Lymph Nodes/pathology , Macaca fascicularis , Male , Mice , Mice, Inbred BALB C , Mucoproteins/drug effects , Nephrosis, Lipoid/etiology , Recombinant Proteins/administration & dosage , Recombinant Proteins/toxicity , Spleen/drug effects , Spleen/pathology , Time Factors , Uromodulin
17.
Cytometry A ; 52(1): 28-35, 2003 Mar.
Article in English | MEDLINE | ID: mdl-12596249

ABSTRACT

BACKGROUND: Troglitazone (TRO), a thiazolidinedione (TZD) peroxisome proliferator-activated receptor gamma agonist, was recently withdrawn from the market because of rare but serious hepatotoxicity. Previous studies investigating the cytotoxicity of TRO in cultured rat hepatocytes have conjectured about the role of oxidative stress in TRO-induced hepatotoxicity. Therefore, we investigated whether TRO induces oxidative stress and, if so, the portion of the TRO molecule responsible for the induction of oxidative stress. METHODS: Novikoff rat hepatoma (N1S1) cells were incubated with TRO, troglitazone quinone (TQ), thiazolidinedione-phenoxyacetic acid (TD-PAA) or rosiglitazone (RSG). Membrane peroxidation, intracellular glutathione (GSH) content, and cellular viability were monitored simultaneously by multiparameter flow cytometry. RESULTS: TRO and TQ increased membrane peroxidation, decreased intracellular GSH, and decreased cell viability in a concentration-dependent manner. In contrast, TD-PAA and RSG neither increased membrane peroxidation nor induced loss of cell viability. In addition, TRO caused a concentration-dependent increase in intracellular superoxide generation accompanied by a collapse in mitochondrial membrane potential. CONCLUSION: Multiparameter flow cytometric evaluation of N1S1 cells indicated that the chromane ring of TRO, rather than the TZD moiety, may be responsible for oxidative stress and suggested that a direct effect on mitochondrial physiology may play a role in TRO-mediated hepatotoxicity.


Subject(s)
Carcinoma, Hepatocellular/metabolism , Chromans/pharmacology , Oxidative Stress , Thiazolidinediones/pharmacology , Animals , Cell Line , Cell Line, Tumor , Cell Membrane/metabolism , Coloring Agents/pharmacology , Dose-Response Relationship, Drug , Fibrinolytic Agents/pharmacology , Flow Cytometry , Fluoresceins/pharmacology , Fluorescent Dyes/pharmacology , Glutathione/metabolism , Membrane Potentials , Mitochondria/metabolism , Models, Chemical , Oxygen/metabolism , Phenanthridines/chemistry , Propidium/pharmacology , Rats , Rosiglitazone , Superoxides/metabolism , Troglitazone
18.
Toxicol Sci ; 69(1): 131-8, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12215667

ABSTRACT

Troglitazone (TRO), a member of the thiazolidinedione class of drugs, has been associated with hepatotoxicity in patients. The following in vitro study was conducted to investigate the effects of TRO on mitochondrial function and viability in a human hepatoma cell line, HepG2. TRO induced a concentration- and time-dependent increase in cell death, as measured by lactate dehydrogenase release. Exposure to 50 or 100 micro M TRO produced total loss of cell viability within 5 h. Preincubation of HepG2 cells with P450 inhibitors did not significantly protect against TRO-induced cell death suggesting that P450 metabolism was not required to induce cell death. Preincubation with the mitochondrial permeability transition inhibitor, cyclosporin A, provided complete protection against TRO-induced cell death. Our results also indicated that TRO produced concentration-dependent decreases in cellular ATP levels and mitochondrial membrane potential (MMP). Ultrastructural analysis demonstrated that TRO induced mitochondrial changes at concentrations of > or =10 micro M after 2 h. Decreased MMP and altered mitochondrial morphology occurred at time points that preceded cell death and at sublethal concentrations of TRO. These observations in HepG2 cells suggest that TRO disrupts mitochondrial function, leading to mitochondrial permeability transition and cell death.


Subject(s)
Chromans/pharmacology , Hypoglycemic Agents/pharmacology , Mitochondria, Liver/drug effects , Thiazoles/pharmacology , Thiazolidinediones , Adenosine Triphosphate/metabolism , Cell Death/drug effects , Cell Survival/drug effects , Cytochrome P-450 Enzyme Inhibitors , Dose-Response Relationship, Drug , Enzyme Inhibitors/pharmacology , Humans , Microscopy, Confocal , Microscopy, Electron , Mitochondria, Liver/ultrastructure , Permeability , Time Factors , Troglitazone , Tumor Cells, Cultured
19.
Stroke ; 33(2): 578-85, 2002 Feb.
Article in English | MEDLINE | ID: mdl-11823673

ABSTRACT

BACKGROUND AND PURPOSE: Although used clinically to prevent stroke, there are few examples of anticoagulant investigations in the treatment of acute thromboembolic stroke in animal models. The treatment of thromboembolic stroke in experimental models has been investigated almost exclusively around the use of tissue plasminogen activator (tPA). In this study, using a rat thromboembolic stroke model, we investigated the use of an inhibitory anti-factor IX(a) monoclonal antibody (SB 249417) for the treatment of thromboembolic stroke and compared its efficacy to that of tPA. METHODS: Stroke was initiated by delivering 6 clots into the internal carotid artery. After 2, 4, or 6 hours, rats received either intravenous vehicle, 10.0 mg/kg tPA, or 1.0, 2.0, or 3.0 mg/kg SB 249417. At 24 hours after stroke, infarct volumes and neurological deficits were assessed. RESULTS: Treatment with tPA 2, 4, or 6 hours after stroke reduced infarct volumes by 35% (P=NS), 45%, and 39%, respectively. tPA treatment did not improve neurological deficits at any time point. Treatment with SB 249417 (3.0 mg/kg) 2, 4, or 6 hours after stroke reduced infarct volumes by 44%, 50%, and 13% (P=NS), respectively. Neurological deficits were reduced by 49%, 42%, and 13% (P=NS), respectively. Neither mortality nor hemorrhage was affected by either treatment. CONCLUSIONS: The data indicate that the inhibition of factor IX(a) within 4 hours of thromboembolic stroke produced a more favorable outcome than tPA. When treatment was initiated 6 hours after stroke, the benefits of factor IX(a) inhibition were lost, whereas tPA continued to suppress lesion development, albeit without a corresponding improvement in functional deficits. This study suggests that cerebral ischemia and the resultant perfusion deficit are exacerbated by the activation of blood coagulation and that anticoagulants like SB 249417 may find utility in the treatment of ischemic stroke.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Factor IXa/antagonists & inhibitors , Fibrinolytic Agents/therapeutic use , Stroke/therapy , Thromboembolism/therapy , Acute Disease , Animals , Behavior, Animal/drug effects , Disease Models, Animal , Disease Progression , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Enzyme Activation/drug effects , Neurologic Examination , Plasminogen Activators/therapeutic use , Prosencephalon/blood supply , Prosencephalon/drug effects , Prosencephalon/pathology , Rats , Stroke/etiology , Stroke/physiopathology , Survival Rate , Thromboembolism/complications , Thromboembolism/pathology , Time Factors , Tissue Plasminogen Activator/therapeutic use , Treatment Outcome
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